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firebird-mirror/src/common/classes/ClumpletWriter.cpp
2006-04-06 08:18:53 +00:00

301 lines
6.8 KiB
C++

/*
* PROGRAM: Client/Server Common Code
* MODULE: ClumpletWriter.cpp
* DESCRIPTION: Secure handling of clumplet buffers
*
* The contents of this file are subject to the Initial
* Developer's Public License Version 1.0 (the "License");
* you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
* http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
*
* Software distributed under the License is distributed AS IS,
* WITHOUT WARRANTY OF ANY KIND, either express or implied.
* See the License for the specific language governing rights
* and limitations under the License.
*
* The Original Code was created by Nickolay Samofatov
* for the Firebird Open Source RDBMS project.
*
* Copyright (c) 2004 Nickolay Samofatov <nickolay@broadviewsoftware.com>
* and all contributors signed below.
*
* All Rights Reserved.
* Contributor(s): ______________________________________.
*
*
*/
#include "firebird.h"
#include "../common/classes/ClumpletWriter.h"
#include "fb_exception.h"
#include "../jrd/ibase.h"
namespace Firebird {
ClumpletWriter::ClumpletWriter(Kind k, size_t limit, UCHAR tag) :
ClumpletReader(k, NULL, 0), sizeLimit(limit), dynamic_buffer(getPool())
{
initNewBuffer(tag);
rewind();
}
void ClumpletWriter::initNewBuffer(UCHAR tag)
{
switch (kind)
{
case SpbAttach:
if (tag != isc_spb_version1)
{
dynamic_buffer.push(isc_spb_version);
}
dynamic_buffer.push(tag);
break;
case Tagged:
case Tpb:
dynamic_buffer.push(tag);
break;
default:
break;
}
}
ClumpletWriter::ClumpletWriter(Kind k, size_t limit, const UCHAR* buffer, size_t buffLen, UCHAR tag) :
ClumpletReader(k, NULL, 0), sizeLimit(limit), dynamic_buffer(getPool())
{
if (buffer && buffLen) {
dynamic_buffer.push(buffer, buffLen);
}
else {
initNewBuffer(tag);
}
rewind();
}
void ClumpletWriter::reset(UCHAR tag)
{
dynamic_buffer.shrink(0);
initNewBuffer(tag);
rewind();
}
void ClumpletWriter::reset(const UCHAR* buffer, size_t buffLen)
{
dynamic_buffer.clear();
if (buffer && buffLen) {
dynamic_buffer.push(buffer, buffLen);
}
else {
UCHAR tag = (kind == SpbStart || kind == UnTagged) ? getBufferTag() : 0;
initNewBuffer(tag);
}
rewind();
}
void ClumpletWriter::size_overflow()
{
fatal_exception::raise("Clumplet buffer size limit reached");
}
void ClumpletWriter::insertInt(UCHAR tag, SLONG value)
{
#if defined(WORDS_BIGENDIAN)
UCHAR bytes[4];
const UCHAR* ptr = reinterpret_cast<UCHAR*>(&value);
bytes[0] = ptr[3];
bytes[1] = ptr[2];
bytes[2] = ptr[1];
bytes[3] = ptr[0];
insertBytesLengthCheck(tag, bytes, sizeof(bytes));
#else
insertBytesLengthCheck(tag, reinterpret_cast<UCHAR*>(&value), sizeof(value));
#endif
}
void ClumpletWriter::insertBigInt(UCHAR tag, SINT64 value)
{
#if defined(WORDS_BIGENDIAN)
UCHAR bytes[8];
const UCHAR* ptr = reinterpret_cast<UCHAR*>(&value);
bytes[0] = ptr[7];
bytes[1] = ptr[6];
bytes[2] = ptr[5];
bytes[3] = ptr[4];
bytes[4] = ptr[3];
bytes[5] = ptr[2];
bytes[6] = ptr[1];
bytes[7] = ptr[0];
insertBytesLengthCheck(tag, bytes, sizeof(bytes));
#else
insertBytesLengthCheck(tag, reinterpret_cast<UCHAR*>(&value), sizeof(value));
#endif
}
void ClumpletWriter::insertString(UCHAR tag, const string& str)
{
insertString(tag, str.c_str(), str.length());
}
void ClumpletWriter::insertPath(UCHAR tag, const PathName& str)
{
insertString(tag, str.c_str(), str.length());
}
void ClumpletWriter::insertString(UCHAR tag, const char* str, size_t length)
{
insertBytesLengthCheck(tag, reinterpret_cast<const UCHAR*>(str), length);
}
void ClumpletWriter::insertBytes(UCHAR tag, const UCHAR* bytes, size_t length)
{
insertBytesLengthCheck(tag, bytes, length);
}
void ClumpletWriter::insertByte(UCHAR tag, const UCHAR byte)
{
insertBytesLengthCheck(tag, &byte, 1);
}
void ClumpletWriter::insertBytesLengthCheck(UCHAR tag, const UCHAR* bytes, size_t length)
{
// Check that we're not beyond the end of buffer.
// We get there when we set end marker.
if (cur_offset > dynamic_buffer.getCount()) {
usage_mistake("write past EOF");
return;
}
// Check length according to clumplet type
ClumpletType t = getClumpletType(tag);
UCHAR lenSize = 0;
switch (t)
{
case TraditionalDpb:
if (length > 0xFF)
{
string m;
m.printf("attempt to store %d bytes in a clumplet with maximum size 255 bytes", length);
usage_mistake(m.c_str());
return;
}
lenSize = 1;
break;
case SingleTpb:
if (length > 0)
{
usage_mistake("attempt to store data in dataless clumplet");
return;
}
break;
case StringSpb:
if (length > 0xFFFF)
{
string m;
m.printf("attempt to store %d bytes in a clumplet", length);
usage_mistake(m.c_str());
return;
}
lenSize = 2;
break;
case IntSpb:
if (length != 4)
{
usage_mistake("attempt to store %d bytes in clumplet, need 4");
return;
}
break;
case ByteSpb:
if (length != 1)
{
usage_mistake("attempt to store %d bytes in clumplet, need 1");
return;
}
break;
}
// Check that resulting data doesn't overflow size limit
if (dynamic_buffer.getCount() + length + lenSize + 1 > sizeLimit) {
size_overflow();
}
// Insert the data
dynamic_buffer.insert(cur_offset++, tag);
switch (lenSize)
{
case 1:
dynamic_buffer.insert(cur_offset++, static_cast<UCHAR>(length));
break;
case 2:
{
USHORT value = static_cast<USHORT>(length);
fb_assert(sizeof(USHORT) == 2);
#if defined(WORDS_BIGENDIAN)
UCHAR b[2];
const UCHAR* ptr = reinterpret_cast<UCHAR*>(&value);
b[0] = ptr[1];
b[1] = ptr[0];
dynamic_buffer.insert(cur_offset, b, sizeof(b));
#else
dynamic_buffer.insert(cur_offset, reinterpret_cast<UCHAR*>(&value), sizeof(value));
#endif
cur_offset += 2;
}
break;
}
dynamic_buffer.insert(cur_offset, bytes, length);
cur_offset += length;
}
void ClumpletWriter::insertTag(UCHAR tag)
{
insertBytesLengthCheck(tag, 0, 0);
}
void ClumpletWriter::insertEndMarker(UCHAR tag)
{
// Check that we're not beyond the end of buffer.
// We get there when we set end marker.
if (cur_offset > dynamic_buffer.getCount()) {
usage_mistake("write past EOF");
return;
}
// Check that resulting data doesn't overflow size limit
if (cur_offset + 1 > sizeLimit) {
size_overflow();
}
dynamic_buffer.shrink(cur_offset);
dynamic_buffer.push(tag);
cur_offset += 2; // Go past EOF to indicate we set the marker
}
void ClumpletWriter::deleteClumplet()
{
const UCHAR* clumplet = getBuffer() + cur_offset;
const UCHAR* buffer_end = getBufferEnd();
// Check for EOF
if (clumplet >= buffer_end) {
usage_mistake("write past EOF");
return;
}
if (buffer_end - clumplet < 2) {
// It appears we're erasing EOF marker
dynamic_buffer.shrink(cur_offset);
}
else {
dynamic_buffer.removeCount(cur_offset, getClumpletSize(true, true, true));
}
}
} // namespace